JP2607756B2 - Device to position transducer on track of magnetic disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for positioning an arm on a track of a disk. More particularly, the present invention relates to a technique for centering a transducer on a track carrying information on a magnetic disk.

[0002]

2. Description of the Related Art In a disk drive, the disks are typically stacked and mounted on a spindle at a distance from each other. A data head carrying a transducer for reading and writing information on the disk is mounted on an arm, and the arm extends between the disks so that the data head can move on the disk. The arm is attached to the actuator. The actuator is moved to position the data head over the data tracks on the disk.
In order for the data head to read and write information on the disk with high reliability, the transducer must be centered on the data track. Therefore, a closed loop feedback device is desired to position the data head on the track.

One method of using a closed loop feedback circuit to position the data head of a disk drive on a track of a disk is using a dedicated servo metho.
It is called d). This dedicated servo system is dedicated to the task of obtaining one data head and one disk position information in the disk drive. This dedicated data head is called a servo head, and the dedicated disk is called a servo disk. The servo head is connected to a designated servo arm, and this servo arm is connected to the same actuator as the other arms. The servo head is held on the center of the desired track of the servo disk by a closed loop servo device. This closed loop servo system uses feedback from data specially written to the servo disk to properly position the actuator.
The other arms are rigidly attached to the actuator so that they are positioned on the desired tracks of each disk following the servo arms.

[0004]

The servo head is held together with the servo disk in a closed loop feedback system, while the other data heads and other disks in the disk drive ensure that they are properly positioned. Does not benefit from the closed-loop feedback device. Therefore, to function properly, the other disks and heads must be able to maintain their initial position relative to the servo head and servo disk for a long period of time. Maintaining this position is often difficult. This is because the relative head position changes due to extreme temperature or mechanical wear. If all data heads, arms, and disks cannot maintain their relative positions with respect to the servo heads and servo disks, errors due to off-track will occur. Such off-track errors reduce the read margin and also cause data errors.

[0005] Two methods for solving the problem of position change due to extreme temperatures and mechanical wear are described in the related applications. No. 937,270, filed Dec. 3, 1986, entitled "Positioning and Maintaining a Magnetic Recording Transducer in the Track Center of a Disk." No. 390,178, filed Aug. 7, 1989, entitled "Apparatus for Centering Transducers on Tracks of a Magnetic Disk". According to these related applications, a heating member, such as one or two resistors, is embedded in each arm. When electric power is applied to this resistance wire, heat is generated. This heat causes the arm material to expand, causing the arm to flex and move the head along an arc path. This arc path substantially crosses the tracks of the disk. A feedback loop is formed around the head such that the parameters of the readback signal are compared to required values to form an error term. This error term is used to set the power level applied to the heating element. In this way, each arm position is independently controlled.

While such devices have substantial advantages, they also have disadvantages. First, as the capacity of the disk drive is increased, the disk stack mounted on the spindle will typically contain more disks. Also, as the package size of the disk drive decreases, the components within the disk drive must also be reduced. These two factors require that the data arm be made thin. When the thickness of the data arm is reduced, it is small enough to fit into the reduced internal space,
It becomes difficult to provide a resistor large enough to bend the arm and generate the thermal energy required to position the transducer.

[0007] Another disadvantage of previous devices is the power required for installation planning. The amount of current required to heat the arm sufficiently to provide the required positioning must be significant.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a disk drive, in which a transducer carried on a slider on a track of a magnetic disk is heated directly to a data arm in the disk drive. The present invention relates to an apparatus for centering without giving a mark. In the present invention, the arm has a first end for attachment to an actuator that rotates the arm and a second end for attachment to a slider. An arm portion extends between these first and second ends. A shape memory alloy device is connected to the arm portion. Also, a thermal energy applying device is provided for selectively applying thermal energy to the shape memory alloy device and causing a corresponding deformation to the shape memory alloy device. This deformation deflects the arm portion and its second in a plane substantially transverse to the track.
Is moved along an arc path. This movement positions the transducer over the center of the track.

[0009]

FIG. 1 shows an embodiment of the present invention. The thermal compensation arm 10 is shown positioned above a magnetic disk 12. This magnetic disk 12 has a position information area 14
And a plurality of areas. The magnetic disk 12 includes a plurality of tracks 16.

The arm 10 includes a free end 18 and a mounting end 20. A flexure 22 is attached to free end 18 and slider 23. The mounting end 20 of the arm 10 is mounted on an actuator (not shown). The actuator pivots the arm 10 to move the transducer 24 from track to track on the magnetic disk 12.

The arm 10 has a first side 26 and a second side 28. First shape memory alloy wire (SMA wire) 30 and second shape memory alloy wire (SMA wire)
32 are shown mounted on the first side 26 and the second side 28 of the arm 10, respectively. SMA wires 30 and 32 are typically made of 50% titanium and 50% nickel and are
Inches). When the SMA wires 30 and 32 are heated, the SMA wires 30 shrink in length in response to the heat, causing a change in shape. When the SMA wire cools, it returns to its original shape.

Therefore, when the SMA wire 30 is heated, it contracts as a function of the linear expansion coefficient for the particular material used to form the SMA wire 30. This contraction causes the arm 10 to bend or flex. Thus, the transducer 24 is moved in one direction across a particular track 16 located thereunder. When the SMA wire 30 cools, it expands back to its initial length and the transducer 24
Is moved in the opposite direction across the particular track 16.

Similarly, as the SMA wire 32 is heated, its length shrinks as a function of the linear expansion coefficient of the particular material used to form the wire 32. This contraction causes the arm 10 to bend or flex. Accordingly, the transducer 24 is positioned below a particular track 16
In one direction. As the SMA wire 32 cools, it expands to its initial length and the transducer 24 is moved across the transducer in the opposite direction. The movement range described above (typically 1
The order of a few hundredths of a millimeter (on the order of microinches) and the specific direction of travel depends on the geometry and the material that the arm 10 forms, SMA wires 30 and 3
2 depends on the material from which it is formed, and the temperature rise and fall of the SMA wires 30 and 32.

The SMA wires 30 and 32 are heated in various ways. This method includes applying power directly to the SMA wire to generate heat, or using a wire winding heating member, an external heater such as an etched process heater or a conductive polymer. . The method of applying electric power directly to the SMA wire is a preferred embodiment because it requires less electric power than the case of using an external heater member. However, another embodiment for heating the SMA wires 30 and 32 is shown in FIG. FIG. 2 shows a greatly enlarged portion of the SMA 30 wound with two wire winding heating members 31 and 33. The wire wrapping heating members 31 and 33 are typically very thin strip wires and are electrically insulated from the SMA wire 30 by polyimide insulation.

In another embodiment, members 31 and 33
Is a coiled wire that is located near the SMA wire 30 but electrically insulated. In this preferred embodiment, Kapton is used for electrical insulation.

When power is supplied directly to the SMA wire 30, both ends of the wire are connected to a power supply (ie, a power source) of the heating member. This power supply is described in more detail below. If heating members 31 and 33 are used, both ends of those members are connected to a power supply for the heating members. In either case, the power supply is S
When power is supplied to the MA wire 30 or the heating members 31 and 33, heat is generated and the heat energy is reduced to SMA.
The wire 30 is applied to the SMA wire 3
Zero causes the desired shrinkage. When power is removed, the SMA wire 30 cools and is restored to its original initial length.

Although heating of the SMA wire 30 can be provided by only one continuous heating member, the use of multiple heating members is also desirable. By providing a plurality of heating members around the SMA wire 30,
Only the isolated portion of the SMA wire 30 can be heated to elicit a difference in the level of shrinkage in the SMA wire. By selectively controlling a plurality of heating members (eg, heating members 31 and 33), the amount of linear contraction of SMA wire 30, and thus the amount of movement of transducer 24, can be finely controlled.

FIG. 3 shows the movement of the arm 10 during operation. In the illustrated embodiment, the arm 10 is essentially a triangle 3
4 and has a fixed base 36 and two legs. When the SMA wire 30 is heated, it shrinks causing the arm 10 to flex or bend. As a result, the transducer 2 attached to the flexure 22 by the slider 23
The movement occurring at 4 is essentially a movement along the arc 38.

Similarly, when the SMA wire 32 is heated, it shrinks, causing the arm 10 to flex or bend causing the transducer 24 to move along the arc 38. The reference position (the position of the transducer 24 when neither the SMA wire 30 nor the SMA wire 32 is heated) is shown by a solid line in FIG. Two additional positions of the arm 10 are shown in dashed lines. The actual amount of movement is very small, and these two associated positions are greatly exaggerated to illustrate the movement. Further, in order not to clutter FIG.
The dotted line is shown only along the free end 18 of the arm 10. It is important to note that the required travel of the transducer 24 along the arc 38 is generally very small, so that the SMA wires 30 and 32 are only 25.
Only 4mm (1 inch) is needed. However, for clarity of the drawing, the movement of the transducer is shown substantially along the entire length of the arm 10, and the movement of the transducer is greatly exaggerated.

FIG. 4 is an enlarged view of a portion of side 26 of SMA wire 30. The SMA wires 30 and 32 can be mechanically coupled to the arm 10 in various ways. FIG. 4 shows one preferred embodiment. In FIG. 4, the mechanical mounting posts 41 and 43
Are integrally formed on the side 26 of the arm 10. Upon assembly, the first end of the SMA wire 30 is crimped to the first power supply wire 120 by the crimp connector 122. The second end of the SMA wire 30 is crimped to the second power supply wire 124 by the crimp connector 126. SMA wire 3
0 is in electrical contact with power supply wires 120 and 124 in crimp connectors 122 and 126, respectively.

The crimp connectors 122 and 126 are connected to the mounting posts 41 and 43 by screws 128 and 130. Crimp connectors 122 and 126 electrically insulate SMA wire 30 from arm 10. Instead of this, SMA wire 30
Is electrically insulated from arm 10 by using screws 128 and 130 formed using a non-conductive material, and insulating pads 132 and 134 attached between crimp connector and arm 10. Can be. SMA wire 3 with the same mounting structure
2 can also be used.

FIG. 5 shows the arm 10 used in a feedback control circuit. The feedback control circuit includes a controller 44, a heating member power supply 46, a head selector 48, a data head demodulator 50, and a switch 52. The feedback control circuit operates to center the transducer 24 on a specific track 16 of the magnetic disk 12 located below.

Magnetic disk 12 (shown in FIG. 1)
The transducer 24 passes through the position information area 14 every one rotation of. The information is written in the position information area 14 and is decoded (decoded) so as to apply a voltage proportional to the distance that the transducer 24 has moved from the center of the track 16. Therefore, every time the magnetic disk 12 makes one rotation, a burst of position information is read from the magnetic disk 12.

Often the arm 10 will be part of a large disk drive containing multiple arms. Therefore, the arm (or head) selector 48 selects one of the arms to be positioned. When the arm 10 is selected, the position information read from the magnetic disk 12 by the transducer 24 is sent to the data head demodulator 50. The data head demodulator 50 decodes position information obtained from the magnetic disk 12 and generates an analog voltage. This voltage is proportional to the distance that the transducer 24 has moved from the center of the track 16. When the analog switch 52 is closed, the data head demodulator 50
The analog voltage generated by the analog / digital converter is supplied to an analog / digital converter 54. The analog / digital converter 54 provides a digital signal to the controller 44. This signal is a signal indicating the analog voltage provided by the data head demodulator 50.

If transducer 24 were to track directly over the center of transducer 16, the digital signal provided by analog / digital converter 54 would be zero and no position correction would be required. However, if controller 44 determines that the signal provided by analog-to-digital converter 54 is not zero, controller 44 must determine the control value. In order to determine the control value, the control device 44 performs a compensation operation for the compensator 56, and the compensator outputs a correction value based on the operation. The parameters of the compensator 56 are selected to compensate for the digital signal provided by the analog to digital converter 54 such that the control circuit has the desired response.
In the preferred embodiment, compensator 56 is a digital filter. The control device 44 determines the correction value by performing a digital filter operation for the digital filter.

In the illustrated preferred embodiment, the correction value is a voltage. This voltage is provided to a heating member power supply 46. The heating member power supply 46 is supplied to the SMA wires 30 and 32 or, alternatively, the heating members used for the SMA wires 30 and 32 (ie, the heating members 31 and 33 shown in FIG. 2). Power can be separately controlled to generate heat corresponding to a desired control value. Power supply 46 generates a wattage corresponding to the correction value provided by controller 44. SMA wires 30 and 3
2, or a heating member corresponding to these SMA wires 30 and 32, converts the supplied electric power into heat and heats the SMA wires 30 or 32, respectively, to cause contraction. Therefore, the correction value provided to the heating member power supply 46 as volts is the heating member power supply 46, SMA wires 30 and 32 (or SM
Amount of heat generated in the heating members corresponding to the A wires 30 and 32) and the SMA wire 30
And 32 are converted into motion on the order of hundredths of millimeters (micro inches) through the interaction of the contraction forces generated at 32 and 32.

Similarly, if the heating member power supply source 46 is SM
Since the contraction of the A-wires 30 and 32 can be controlled separately, power is normally supplied to only one SMA wire 30 or 32 to correct the position of the arm 10. In other words, S for correction in one direction
Power is supplied to the MA wire 30 and power is supplied to the SMA wire 32 for correction in the other direction. Furthermore, if no correction is required, the SMA wire 30 is
No power is supplied to the A wire 32 at all.

FIG. 6 is a block diagram of a control circuit for controlling the arm position in a disk drive having a plurality of disks and a plurality of arms. The disk drive includes a spindle 58 which carries a plurality of disks 60, 62, 64, 66, 68, 70, 72, 74 and 76 (see the exact designations of disks 60-76). Disks 60-76 are mounted for rotation with spindle 58. The disk drive also includes a plurality of arms 78, 80, 82, 84, 86,
88, 90, and 92 (see the exact designations of arms 78-92), which have the same structure as arm 10 shown in FIGS. Each of the arms 78-92 includes a pair of flexures 22 and a pair of transducers 24 (only arm 86 has one flexure 22).
And one transducer 24). The transducer moves over the surface of the disks 60-76. Further, the arms 78-92 are mounted on an actuator 94 which pivots the arms 78-92 from track to track on the disks 60-76.

The control circuit includes a controller 44, a heating member power supply 46, a head selector 48, a data head demodulator 50, an analog switch 52, an analog / digital converter 54, a servo head demodulator 96, an actuator driver 98, Input / output logic circuit 100
Contains.

In the illustrated embodiment, arm 86 acts as a servo arm. The transducer attached to the arm 86 reads servo head position information from the servo disk 68. The servo head position information is supplied to a servo head demodulator 95, which decodes the position information and supplies an analog voltage indicating the position of the servo arm 86 to the analog switch 52. At regular intervals, controller 44 provides a signal to input / output logic circuit 100 to convert the analog voltage provided by servo head demodulator 96 to analog / digital converter 54.
To be transmitted. The analog / digital converter 54 provides the controller 44 with a digital signal indicating the analog voltage provided by the servo head demodulator 96. Based on this digital signal, the control device 44 calculates a correction value and supplies it to the actuator driving device 98. Actuator drive 98 drives actuator 94 to rotate actuator 94 in response to this correction so as to maintain transducer 24 of servo arm 86 on the center of the particular track 16 being moved.

At one point during one revolution of the spindle 58, the signal from the servo head demodulator 96 provides data head position information on the disks 60-66 and 70-76.
That the transducers 24 of the arms 78-84 and 88-92 are about to pass through the reporting area 14;
Be instructed. At this position, the input / output logic circuit 100 switches the head selector 48 to read the position information from the desired arms 78-84 and 88-92. As mentioned above, the data head demodulator decodes the information provided by the selected arm and converts it to a voltage proportional to the distance that the transducer 24 of the selected arm has moved from the track 16. The control device 44 switches the analog switch 52 by the input / output logic circuit 100 to switch the data head demodulator 5
The decoded information is sampled by making the signal given by 0 data. After this information is converted to a digital signal by the analog / digital converter 54, the controller 44 performs a digital filter operation to determine a correction value for the selected arm.

The correction value is provided to a heating member power supply 46. The heating member power supply 46 supplies sufficient power to generate the amount of heat required to cause the required SMA wire corresponding to the selected arm to contract. This contraction causes the transducer 24 of the selected arm to be moved a distance commensurate with the required correction value.

During the next revolution of the spindle 58, the input / output logic circuit 100 causes the head selector 48 to select another arm to be corrected. The transducer position of the arm thus selected is sampled by the controller 44 and the heating member power supply 46
The correction is performed via. Similarly, for each subsequent rotation of the spindle 58, the head selector 48 selects another arm to be corrected. After all arms have been sampled and corrected, such a selection sequence by head selector 48 is repeated. This results in a constant sampling ratio for each arm.

FIG. 7 shows another preferred embodiment of the positioning device of the present invention. The arm 10 shown in FIG. 7 is the same as the arm shown in FIG. 3, and has the same reference numerals. The only difference is that SMA wires 30 and 32
Are not attached to sides 26 and 28 of arm 10. Instead, SMA wires 30 and 32 are attached to opposite sides of flexure 22. This embodiment has a completely different advantage. As described with reference to FIG. 6, and as shown in FIG. 8, a pair of flexures 22 and 22 'are connected to each arm, and each flexure 22 and 22' is connected to a slider 23 or 23 '. It is common to connect to the transducer 24 or 24 'via a. If the SMA wires 30 and 32 were connected to the sides 26 and 28 of the arm 10, the positioning obtained by heating either SMA wires 30 or 32 would require the transducers 24 and 24 'to be in their respective counterparts. Will be positioned together with respect to the track 16 to be adjusted.

However, in practice, only one of the transducers 24 or 24 'attached to each arm needs to be corrected. In the embodiment shown in FIG. 7, each flexure 22 and 22 'is a pair of SMA wire 3
0 and 32 or 30 'and 32' respectively. Therefore, by separately controlling the heating of SMA wires 30 and 32 and SMA wires 30 'and 32', transducers 24 and 2
The positioning of the 4 'is separately controlled. This greatly improves the tracking accuracy of the transducer in the disk drive.

FIG. 9 shows still another preferred embodiment of the positioning device of the present invention. The arm 10 shown in FIG.
Are the same as the arms shown in FIGS. 3 and 7, and are denoted by the same reference numerals. However, instead of having one SMA wire attached to each side 26 and 28 of arm 10, the embodiment shown in FIG. 9 has multiple SMA wires attached to side 26 of arm 10 and similarly multiple SMs.
An A-wire is attached to side 28 of arm 10.

SMA wires 102 and 104 are attached to side 26 of arm 10, respectively. Heating of the SMA wires 102 and 104 is controlled separately.
Therefore, the amount of bending or bending of the arm 10 can be controlled stepwise. For example, to achieve a large bend, both SMA wires 102 and 104 are heated. Alternatively, when a small bend is required, the SMA wire 102 or 104 is heated. SMA wire 104 is SMA wire 1
02 can be made sufficiently shorter. Therefore,
By individually controlling the application of thermal energy to the SMA wires 102 and 104, coarse and fine positioning can be achieved.

Similarly, SMA wires 106 and 10
8 are both mounted on side 28 of arm 10. SM
A wires 106 and 108 are SMA wires 102
And 104 can be controlled separately, and the gradual deflection of the arm 10 can be controlled. Sides 26 and 2 of arm 10
8 with a plurality of SMA wires, the movement of the transducer 24 along the arc 38 is reduced to one SM.
More finer control can be achieved if A-wires are provided on sides 26 and 28 of arm 10. Thereby, higher accuracy can be obtained in positioning the transducer 24 on the track 16 of the magnetic disk 12.

A still further embodiment of the present invention is shown in FIG. This is very similar to the embodiment of FIGS. The only difference is that wires 30, 32, 30 'and 32' are connected at one end to flexures 22 and 22 'and at the other end to arm 10.
According to this embodiment, the transducers 24 and 2 are similar to the embodiment described with reference to FIGS.
The minute positioning of 4 'can be individually performed.

[0040]

The present invention has the advantage that the fine positioning of the transducer in the disk drive can be thermally controlled without the need to apply thermal energy directly to the data arm itself. Instead of a data arm, heat energy is applied to a shape memory alloy member attached to the arm. To cause the shape memory alloy member to be linear requires less heat than to cause thermal expansion to the arm itself. Therefore, positioning can be achieved using a small heating member. Alternatively, positioning can be performed by omitting the heating member and applying power directly to the shape memory alloy member. This allows for fine positioning of the individual data arms of the disk drive, and in some embodiments fine positioning of the individual transducers. On the other hand, the package size of the disk drive can be reduced, and the thickness of the arm inside the disk drive can be reduced.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

[Brief description of the drawings]

FIG. 1 is a top view of an arm positioned on a magnetic disk showing a centering device or positioning device according to the present invention.

FIG. 2 is a fragmentary view of a greatly enlarged embodiment of the shape memory alloy device of the present invention.

FIG. 3 is an enlarged view of the arm shown in FIG. 1;

FIG. 4 is a greatly enlarged partial view of the arm showing one embodiment of the connection between the shape memory alloy device and the arm.

FIG. 5 is a block diagram showing the arm of FIG. 1 in the block diagram of the feedback loop;

FIG. 6 is a block diagram of a feedback control loop used with multiple arms.

FIG. 7 is a top view showing a second embodiment of the centering device or positioning device of the present invention.

FIG. 8 is a side view of the pair of flexures shown in FIG. 5;

FIG. 9 is a top view of another embodiment of the centering or positioning device of the present invention.

FIG. 10 is a top view of yet another embodiment of a centering or positioning device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Arm 12 Magnetic disk 14 Position area 16 Track 23 Slider 24 Transducer 26, 28 Side or side of arm 30, 32 SMA wire 31, 33 Heating member 38 Arc path 44 Controller 46 Heating member power supply 48 Head selector Reference Signs List 50 data head demodulator 52 switch 54 analog / digital converter 56 compensator 58 spindle 60-76 disk 78-92 arm 94 actuator 96 servo head demodulator 98 actuator drive device 100 input / output logic circuit 102, 104, 106, 108 SMA Wires 120, 124 Power supply wires 122, 126 Crimp connectors 132, 134 Insulation pads

Claims (44)

(57) [Claims] An apparatus for positioning a transducer carried on a slider on a track of a magnetic disk, the first end being adapted to be attached to an actuator for rotating an arm. And a second end adapted to be attached to the slider,
An arm portion extending between the first end portion and the second end portion, the arm portion being connected to the arm portion and deforming in response to thermal energy
A shape memory alloy device , wherein the arm is deformed when deformed.
And selectively applying thermal energy to the shape memory alloy device to cause deformation of the shape memory alloy device accordingly, thereby deforming the arm portion and substantially traversing the track preparative second end along an arc path in a plane
Means for moving the transducer to a transducer position on the center of the rack . An apparatus for positioning a transducer on a track of a magnetic disk. 2. The device of claim 1, wherein the arm portion is adapted to be coupled to an actuator, and the arm portion is coupled to the data arm portion at a first end. A first flexure having a second end adapted to be coupled to the first slider, comprising: a first flexure having a second end adapted to be coupled to the first slider; Positioning device. 3. The apparatus according to claim 2, wherein the shape memory alloy device is connected to the data arm portion, and the transducer is positioned on the track of the magnetic disk. 4. The device according to claim 3, wherein the shape memory alloy device is a first shape memory alloy member connected to one side of the data arm portion, the deformation of which is the first shape memory alloy member. The second end of the flexible body along the arc path to the first end.
And a second shape memory alloy member coupled to the other side of the data arm portion that is generally opposite to the one side, the first shape memory alloy member being configured to move in the direction of
A second deformation wherein the deformation causes the second end of the first flexure to extend along the arc path in a direction generally opposite to the first direction.
2. A device for positioning a transducer on a track of a magnetic disk, comprising: a second shape memory alloy member adapted to be moved in the direction of. 5. The apparatus of claim 2, wherein the shape memory alloy device is coupled to the first flexure, wherein the transducer is positioned on a track of the magnetic disk. 6. The device according to claim 5, wherein the shape memory alloy device is a first shape memory alloy member connected to one side of the first flexible member, and the deformation of the first shape memory alloy member is performed. First
A first shape memory alloy member adapted to move a second end of the flexure in a first direction along the arc path; and generally opposite the one side of the first flexure. A second shape memory alloy member coupled to the other side, the deformation of which causes the second end of the first flexure to generally extend with the first direction along the arc path. An apparatus for positioning a transducer on a track of a magnetic disk, comprising: a second shape memory alloy member adapted to move in a second direction which is an opposite direction. 7. The apparatus of claim 6, wherein the arm portion is further connected at a first end to a data arm and adapted to be connected to a second slider. An apparatus for positioning a transducer on a track of a magnetic disk, comprising: a second flexure having an end. 8. The device according to claim 7, wherein the shape memory alloy device further comprises: a second shape memory alloy device connected to the second flexure. A device that positions the transducer on the track of the magnetic disk. 9. The device according to claim 8, wherein the second shape memory alloy device is a third shape memory alloy member connected to one side of the second flexure, A third shape memory alloy member whose deformation causes the second end of the second flexure to move in a first direction along the arc path; and the one side of the second flexure. A fourth shape memory alloy member coupled to the other side, which is generally the opposite side, the deformation of which causes the second end of the second flexure to move along the arc path along the first shape memory member. A fourth shape memory alloy member adapted to be moved in a second direction which is generally opposite to the direction, wherein the transducer is positioned on a track of the magnetic disk. apparatus. 10. The apparatus according to claim 8, wherein:
Means for selectively applying thermal energy include: selectively applying thermal energy to the first shape memory alloy device to cause a corresponding deformation thereof to deflect the first flexure to cause the truck to flex. A first energy means for moving the second end of the first flexure along the arc path in a substantially transverse plane; and selectively applying heat energy to the second shape memory alloy device. To cause a corresponding deformation thereof to deflect the first flexure and move the second end of the first flexure along the arc path in a plane substantially transverse to the track. An apparatus for positioning a transducer on a track of a magnetic disk. 11. The apparatus according to claim 1, wherein:
A mechanical coupling device for coupling the shape memory alloy device to the arm portion such that at least a portion of the shape memory alloy device is spaced from the arm portion. A device to position the transducer on. 12. The apparatus according to claim 1, wherein:
Further, a position indicating device for providing a position signal indicating that the transducer is performing off-center tracking, and a thermal control for selectively controlling the amount of heat applied to the shape memory alloy device as a function of the position signal. An apparatus for positioning a transducer on a track of a magnetic disk, comprising: an apparatus; 13. The apparatus according to claim 12, wherein the magnetic disk includes a plurality of sectors for containing information, and wherein the position data is stored in at least one sector of the magnetic disk. An apparatus for positioning a transducer on a track of a magnetic disk, wherein the data indicates the distance from the center of the track to the transducer. 14. The apparatus according to claim 13, wherein the position indicating device is adapted to transfer the position data passing by the transducer as it passes over the sector containing the position data. An apparatus for positioning a transducer on a track of a magnetic disk, comprising means for emitting a modulated signal representative of the signal. 15. The apparatus according to claim 14, wherein the position pointing device further comprises: a demodulator for demodulating the modulated signal and generating a demodulated position signal. Device that positions a transducer on the tracks of a rotating magnetic disk. 16. The apparatus according to claim 15, wherein the thermal control device compensates the demodulated position signal to provide a compensated position signal, and determines a correction value based on the compensated position signal. Correction device, wherein the correction value represents the distance of the transducer from the track center, and the power guided to the means for selectively applying thermal energy as a function of the correction value. An apparatus for positioning a transducer on a track of a magnetic disk, comprising: a thermal control power supply that varies. 17. The apparatus according to claim 1, wherein:
Means for selectively applying thermal energy, comprising: a controllable power supply coupled to the shape memory alloy device to control power directed to the shape memory alloy device. A device that positions a transducer on the tracks of a magnetic disk. 18. The apparatus according to claim 17, wherein the means for selectively applying thermal energy comprises: a controllable power supply for receiving power provided by the controllable power supply. Connected to
A device for positioning a transducer on a track of a magnetic disk, comprising: a resistance heating member device in heat transfer contact with a shape memory alloy device. 19. The apparatus according to claim 18, wherein the resistance heating member device is a plurality of resistance heating members each in heat transfer contact with a shape memory alloy device, wherein the resistance heating member device is controlled by a controllable power supply. An apparatus for positioning a transducer on a track of a magnetic disk, comprising: a resistance heating member capable of selectively controlling electric power guided to each resistance heating member. 20. The apparatus of claim 19, wherein the shape memory alloy device includes a plurality of shape memory alloy members connected to generally opposite sides of the arm portion. A device that positions a transducer on a track. 21. The apparatus of claim 20, wherein at least one resistance heating member is in heat transfer contact with each of the plurality of shape memory alloy members. A device that positions the transducer. 22. The apparatus according to claim 21, wherein a plurality of resistance heating members are in heat transfer contact with each of the plurality of shape memory alloy members. A device that positions the producer. 23. The apparatus according to claim 2, wherein
Positioning the transducer on a track of a magnetic disk wherein a shape memory alloy device is connected at a first end to a data arm portion and at a second end to a first flexure. Equipment to do. 24. An apparatus for controlling the tracking of a plurality of transducers carried by a plurality of sliders on a track of a plurality of magnetic disks, wherein at least one transducer is associated with each of the magnetic disks. A first end adapted to be attached to an actuator for rotating the arm and a second end adapted to be attached to one of the plurality of sliders. And each has an arm portion ,
An arm portion extends between the first and second ends
A plurality of shape memory alloy members, at least one shape memory alloy member connected to each of the arm portions, and selectively applying thermal energy to the selected shape memory alloy members. Causing a corresponding deformation to selectively deflect the arm portion, moving the second end along an arcuate path in a plane substantially parallel to the corresponding disk and substantially across the track. Means for selectively applying said thermal energy for positioning each transducer on its center. 25. The apparatus according to claim 24, wherein each arm portion is coupled to a data arm portion at a first end and a data arm portion adapted to be coupled to an actuator; A first flexure having a second end adapted to be coupled to the first slider. 26. The tracking control device according to claim 25, wherein each data arm portion is connected to at least one independent shape memory alloy member. 27. The apparatus according to claim 26, wherein a first shape memory alloy member is connected to one side of each data arm member, and wherein deformation of the first shape memory alloy member is the first shape memory alloy member. A second end of the flexure body is moved in a first direction along the arc path, and a second shape memory alloy member is generally coupled to the one side of the data arm portion. And the second shape memory alloy member deforms the second end of the first flexure generally opposite the first direction along the arc path. The tracking control device is adapted to be moved in a second direction which is a direction of the tracking control. 28. The tracking control apparatus according to claim 25, wherein each first flexure is connected to at least one independent shape memory alloy member. 29. The apparatus according to claim 28, wherein a first shape memory alloy member is connected to one side of the first flexure, and the deformation of the first shape memory alloy member is responsive. A second end of the first flexible member to be moved in the first direction along the arc path, and a second shape memory alloy member is provided on the one side of the first flexible member. Is connected to the other side which is generally opposite to the first side, and the second end of the first flexible member corresponding to the deformation of the second shape memory alloy member is moved along the arc path along the first side. In a second direction which is generally opposite to the direction of
A tracking control device, characterized in that: 30. The apparatus of claim 29, wherein each of the arm portions is further coupled at a first end to a data arm and adapted to be coupled to a second slider. 2. A tracking control device comprising: a second flexure having two end portions. 31. The tracking control device according to claim 30, wherein at least one shape memory alloy member is connected to the second flexure of each arm portion. 32. The apparatus according to claim 31, wherein a third shape memory alloy member is coupled to one side of a corresponding second flexure, and the third shape memory alloy member is deformed. Move the second end of the corresponding second flexure in the first direction along the arc path;
A fourth shape memory alloy member is coupled to the other side of the corresponding second flexure, which is generally opposite to the one side;
The second end of the second flexure corresponding to the deformation of the fourth shape memory alloy member is moved along the arc path in a second direction which is generally opposite to the first direction. A tracking control device adapted to be moved. 33. The apparatus according to claim 24, wherein the shape memory alloy member is coupled to the arm portion such that at least a portion of each of the shape memory alloy members is spaced from the arm portion. A tracking control device characterized by the above-mentioned. 34. The apparatus according to claim 24, further comprising: an arm selection device for selecting an arm to be corrected; a transducer coupled to the selected arm performs off-center tracking. A position indicating device for giving a position signal indicating that the operation is being performed, and a heat control device for selectively changing the amount of heat applied to the shape memory alloy device connected to the selected arm as a function of the position signal A tracking control device, comprising: 35. The apparatus according to claim 34, wherein each magnetic disk has a plurality of sectors for containing information, and wherein the position pointing device corresponds to the selected arm. Position data recorded in at least one sector of a magnetic disk,
Tracking data indicating a distance from a center of the track to a transducer coupled to the selected arm. 36. The apparatus according to claim 35, wherein the position signal is coupled to a selected arm as the transducer passes over a sector containing position data. A modulation signal representing position data passing through the tracking control device. 37. The apparatus of claim 36, wherein the position pointing device further comprises: a demodulator for demodulating the modulated signal to produce a demodulated position signal. A tracking control device. 38. The apparatus according to claim 37, wherein the thermal control device compensates the demodulation position signal to provide a compensation position signal, and determines a correction value based on the compensation position signal. And a shape memory alloy member connected to the selected arm, wherein the correction value represents a distance from a track center to a transducer connected to the selected arm, and a shape memory alloy member connected to the selected arm. A thermal control power supply that changes the power guided to as a function of the correction value. 39. The apparatus of claim 24, wherein the means for selectively applying thermal energy is coupled to the shape memory alloy member for controlling power conducted to the shape memory alloy member. A tracking control device, comprising: a controllable power supply source. 40. The apparatus of claim 39, wherein the means for selectively applying thermal energy comprises: a controllable power supply for receiving power provided by the controllable power supply. And a resistance heating member device which is connected to the shape memory alloy member and is in heat transfer contact with the shape memory alloy member. 41. The apparatus according to claim 40, wherein the resistance heating member device comprises a plurality of resistance heating members each in heat transfer contact with a shape memory alloy member, the controllable power supply. A resistance heating member configured to selectively control electric power guided to each resistance heating member by a source. 42. The apparatus of claim 41, wherein a shape memory alloy member is connected to generally opposite sides of each arm portion, and wherein each of the plurality of shape memory alloy members is at least In heat transfer contact with one single corresponding resistance heating member, each single resistance heating member corresponding to one of the plurality of shape memory alloy members is independently selectively controllable. And a tracking control device. 43. The tracking control device according to claim 42, wherein each of the plurality of shape memory alloy members is in heat transfer contact with a plurality of corresponding resistance heating members. 44. An apparatus for positioning a transducer carried on a slider on a track of a magnetic disk, the apparatus comprising a first end attached to an actuator for rotating an arm and a slider attached to a first end. A second end having an arm portion extending between the first end and the second end, a positioning device coupled to the arm portion. To apply force to the arm when thermal energy is applied to the positioning device.
A positioning device for applying and removing force from the arm when thermal energy is removed from the positioning device, and means for selectively applying thermal energy to the positioning device, wherein the applying the thermal energy Said means for causing a contraction of the corresponding positioning device, distorting the arm portion and moving its second end along an arc path, and adjusting the position of the second end with respect to the center of the track; An apparatus for positioning a transducer on a track of a magnetic disk, comprising: